13 year old has recurring lower back pain, what could be the causes and treatments?

Are you athletic?: There a lot of reason for low back pain in your age group, the most common are stress injury to lower lumbar vertebra---the key word is recurrent--need careful hx, exam, x rays--ask your general doc first.

Several possiblities: Muscular strain, lumbar ligament inj which is failing to completely heal, si jt. Locked, lumbar vertebral dysf, quadratus lumborum muscle contracture.Must consider other med possibilities, as well, such as kidney problems.A thorough history & phys, incl. Hands-on osteopathic exam may elucidate cause.Osteopathic manipulation or even prolotherapy may prove helpful, if jt., muscular, or ligament cause.

Could be..... : I would note a disc herniation is rare at this age but a spondylolysis/spondylolithesis or benign tumor like an osteioid osteoma could be present. Sometimes autoimmune diseases like rheumatoid arthritis or infection can present like this, initially. A referred pain from a kidney problem/infection or GI problem may also be in the list of possibilities. He needs to be seen if pain restricts him.